The present invention relates to a light source device, specifically a light source device in which, in the case of employing light energy transmitted through an optical conductor cable as a photo-synthesizing light source for cultivating plants, the light energy emitted from the optical conductor cable is effectively dispersed in order to nurture plants.
A proper amount of nutrients and proper atmospheric condition such as light, carbon-dioxide, water, termperature, humidity, etc. are needed for effectively nurturing plants. However, it is often difficult to obtain all of them at once. In order to nurture plants, a suitable ground is needed. In urban districts, as in a megalopolis, it is not so easy to acquire a space for cultivation. It is especially difficult to secure an area that is exposed to the sun.
In order to solve such problems, the present applicant has previously proposed devices to focus the sun's rays by means of a lense or the like and to guide them into an optical conductor, and further to guide the solar rays through the optical conductor to a plant cultivating device to be installed at an optional desired place so as to supply solar ray energy to plants. The present applicant further proposed another plant cultivating device in which artificial light rays were added to the solar rays collected in such a manner as described above. (For instance, refer to the Japanese Patent Application No. 58-119866.)
Utilizing the light energy collected, plants perform photo-synthesis. The nutritious substances produced by the process of photo-synthesis are then transferred to the trunk and fruit of the plants. Such transfer can be effectively realized when there are no light rays available, much oxygen, or low temperatures. Namely, it is necessary to perform the photo-synthesizing reaction and transfer the nutritious substance produced by the photo-synthesizing for the purpose of nurturing the plants. In order for plants to perform photo-synthesis and to transfer nutritious substances to their trunks and fruit, the brightness period (the period of photo-synthesis) and the darkness period (the transfer period) are preferably repeated at predetermined time intervals.
Furthermore, in the case of nurturing plants, if the light rays are supplied to the plants intermittently (several .mu.s to several ms) instead of successively, in other words, the photo-synthesis process consists of a brightness reaction and a darkness reaction and the intensive light rays are supplied to the plants only during the brightness reaction period while the light rays are not supplied or rather weak light rays are supplied to the plants during the darkness reaction period. Thereby growth of plants is promoted as a matter of course.
When the light source device is moved so as to disperse the light rays, the utilization area of the light energy can be enlarged considerably when compared with the illumination of plants by use of a fixed light source. Specifically in the case of employing a light source of the same capacity, the plants can be cultivated over a wider range. Furthermore, in accordance with the movement of the light source device, the shadowed portion of the front leaves changes every moments, and therefore the brightness reaction and the darkness reaction are repeated effectively so that the growth of the plants can be promoted more effectively.